%I #18 Jan 17 2019 10:08:17
%S 8,9,12,41,57,156,201,249,612,956,1617,2064,2091,2547,4512,5696,9608,
%T 11444,20556,33896,77079,89004,251036
%N Numbers n such that 249*2^n-1 is prime.
%H Ray Ballinger and Wilfrid Keller, <a href="http://www.prothsearch.com/riesel1.html">List of primes k.2^n + 1 for k < 300</a>
%H Wilfrid Keller, <a href="http://www.prothsearch.com/riesel2.html">List of primes k.2^n - 1 for k < 300</a>
%H <a href="/index/Pri#riesel">Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime</a>
%H Kosmaj, <a href="http://www.15k.org/riesellist.html">Riesel list k<300</a>.
%o (PARI) is(n)=ispseudoprime(249*2^n-1) \\ _Charles R Greathouse IV_, Jun 13 2017
%K hard,nonn
%O 1,1
%A _N. J. A. Sloane_, Dec 29 1999
%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008